Static electricity and transport of hazardous substances

Static electricity occurs in almost any business. It is caused by poor adhesion of electrically conductive materials. The electrostatic charge (ESC = Electrostatic Charging) of persons and objects are difficult to recognize, however the discharge can be spectacular (ESD = Electro Static Discharge). We all know the unpleasant shocks that can be felt when getting out a car or touching a door handle. Most discharges are harmless to people and products. However, electrostatic discharge can also cause fire, explosion or disruption and/or damage to electronic equipment.

An electrostatic discharge has sufficient energy to ignite or explode a flammable liquid or gas. The required ignition energy to realize a fire or explosion, depends on the type of substance, concentration, temperature and humidity.

In industrial processes, attention should be paid to the transport of hazardous substances. For example liquids with a flashpoint below 55 °C, powders, grains, flour or granules for the production of plastic. Before loading or unloading, the ground cable should always be connected between the supplying and the receiving tank to eliminate the potential difference.

TAS, Tank Automation System:

For safe refuelling, the usage of an earth terminal is not always sufficient. A secure solution continuously monitors the quality of the earth connection. This can be achieved by a ground monitoring control unit.

The ground monitoring control unit consists of an intrinsic safe earthing clamp, to provide a secure discharge. Even in case of corroded barrels, the hardened clamps ensure a proper connection. The red or green light indicates whether the grounding is successful. A signal contact can control an alarm sounder or safety control valve.R.STAHL has various versions of the ground monitoring control unit, suitable for zone 1, 2, 21 and 22.

Applications for earth monitoring system

Highlights

ATEX, IECEx, GOST, UL do Brasil and DNV certified (depending on type)

Suitable for zone 1, 2, 21 and 22 (depending on type)

A secure working environment with video surveillance:

Procedural errors can occur when the work has to be done in extreme warmth, cold or nightly activities, whether or not combined with inevitable time pressure. Competent control is a must!

The monitoring units of STAHL-HMI can be used to visualize the procedures, whether or not supplemented with wireless product- or personal identification (e.g. RF-identification).With a STAHL camera, based on Ethernet/IP, this situation can be followed. By using motion control detection or automatic video recording, the contact time in a hazardous area can be reduced.